Neurological features in overlap syndrome.

We report the frequency of neurological findings in 33 patients with overlap syndrome and describe 2 patients presenting unusual neurological involvement. Five of the 33 patients (15%) had one or more neurological findings. Unilateral trigeminal sensory neuropathy was presents, in 4 patients, in 3 of whom this was the only neurological feature. In the other patient it was associated with other manifestations of central as well as peripheral nervous system involvement, with an overall clinical pattern highly suggestive of a demyelinating disorder. The fifth patient, after an aseptic meningitis-like illness, developed a slowly progressive paraparesis, likewise pointing to a demyelinating disease. Our findings suggest that neurological manifestations, mainly trigeminal neuropathy, are frequent features in overlap syndrome; occasionally, central nervous system involvement mimicking a demyelinating disease may also be observed.